I started a project a couple of weeks ago to strip down and refinish a light oak colored bathroom vanity and stain it ebony.

I used a few coats of Citris stripping gel, along with a bunch of sanding and Citrus paint strip after wash to prepare the surfaces for staining. Then used 100 grain sand paper, then 150, then 220 before lightly rubbed down the wood with a damp cloth to pop the grain and then applied stain, letting it sit following directions of 3-5 minutes before removing. After 4 coats of stain the vanity drawers came out excellent and exactly as I had hoped.

The two doors on the other hand of been a headache. No mater what I do I just cant get them to absorb the stain and come out as dark as the drawers. I resanded them down twice already and reapplied and once they get to about the 3rd coat they just dont absorb any more.

Drawers

Door:

I am at the point now (6 coats) where I think I may have to apply the paint stripper gel again and restart the entire process. Is there anything else I can try to darken them before starting all over?

Good luck with trying to do it that way. Is should have been stipped with 80 grit paper not 100 grit all the way to the bare wood. 100 grit is almost finsh sand paper. By trying to use the citris stripper and to fine a sand paper you may have filled the grain so there's no place for the stain to soak in.
90% of the time people do not have the patiance to sand every last spot of sealer off before tring to restain items. If the sealer is still left on there's no place for the stain to soak in. Plus your trying to stain one of the hardest woods out there. It should be againt the law to paint or stain oak black.

OK, so I coated both doors last night with a heavy dose of Citrus strip then wiped it down about 3 hours later then recoated it again and left it over night. Got up this morning and wiped it clean then used the afterwash. I let the doors dry about 10 hours (it's dry here in the Nevada) and then I went to work with the palm sander. Started with 60 grit went through 3 sander size cut pieces per door. Then I went in by hand doing the router carved areas of the door. Finally, I went over the doors with 120 grit using the palm sander and then finished up by hand again. Whew what a mess...

So now I'm going to let them sit another 24 hours to make sure all the stripper and wash are dry. There is no question that there is no sealer left anywhere on the doors. You can still see some stain marks where it soaked into the grain but we are going nearly black anyway so I'm not worried (or should I be?)

Now my question is after they sit and dry overnight what other steps should I take to make sure that the oak is fully prepared to take the stain this time?

well i went ahead and restained one of the doors starting this morning and thank godness it seems to be taking the stain well after two coats with no blotches. It still needs 1 or 2 more coats to match the drawers though so not out of the woods yet (plus there is still the other door!) i will post pics if it comes out right!